An integrated partial nitrification anaerobic ammonia oxidation reactor was used to explore the feasibility of nitrogen removal from recycled ethanol wastewater. The results show that the integrated partial nitrification-anaerobic ammonia oxidation (PN-ANAMMOX) reactor was started successfully after 40 d under the conditions of pH 7.8±0.5, temperature 30-35℃, and aerobic ORP value 120-150 mV. The total nitrogen removal rate of 0.125 kg·(m3·d)-1 increased to 0.75 kg·(m3·d)-1, Inoculation of mature nitrosated biofilms and anaerobic ammonium oxide granules can accelerate the start of the reactor. The effects of alcohol wastewater on the PN-ANAMMOX reactor were mainly caused by biodegradable TOC, The biodegradable TOC concentration of 100mg·L-1 in alcohol wastewater can reduce the removal rate of total nitrogen from 0.75 kg·(m3·d)-1 to 0.25 kg·(m3·d)-1,this inhibition can be restored. Different concentrations of alcohol wastewater were dosed into the PN-ANAMMOX reactor to acclimate the bacteria. The total nitrogen removal rate first decreased and then increased, as the influent concentration gradient increased, which was beneficial for improving the efficiency of nitrogen removal by extending the HRT and increasing the dissolved oxygen in the PN stage. Finally, the nitrogen removal rate stabilized at 0.65 kg·(m3·d)-1. These results show that PN-ANAMMOX can be used for the treatment of alcohol wastewater.
Keywords: ANAMMOX; alcohol wastewater; biodegradable TOC; biological nitrogen removal; partial nitrification.